The cytosolic cyclic AMP-binding protein of Dictyostelium discoideum will be purified further and characterized. The glycogen phosphorylase, an enzyme induced by cyclic AMP in starving amoebae, will be isolated and antibody against the purified enzyme will be prepared. The antibody will then be employed in an attempt to isolate the relevant polysomes and the mRNA coding for glycogen phosphorylase. If successful, cDNA and genomic DNA complementary to the messenger for glycogen phosphorylase will be prepared with the ultimate aim of studying interactions between the cyclic AMP-binding protein and a gene coding for a protein regulated in its synthesis by cyclic AMP. In unrelated experiments with Escherichia coli the effect of the cyclic AMP-CRP complex on the synthesis of ribosomal proteins will be studied.